That Line-In is OEM on the XLT. I don't use it anymore because this radio has an ipod cable that I have running out from under the dash. The radio takes full control of my iphone when I plug it in. All my music, videos, phone numbers, addresses, etc is accessed through the radio. I can just press a button on the radio and then audibly say a persons name in my contact list and the radio can call them through the bluetooth mic, or I can ask to show driving directions to their house.